In the context of rectifying the rails of a track, several methods such as abrading, cutting, planing and other processes have been known for a long time. One of the methods currently preferred is the abrasive reprofiling of the heads of rails, since it is fast and allows important quantities of metal to be removed. The reprofiling units usually are mounted on a railroad vehicle comprising abrading units equipped with abrasive disks rotated and pressed against the pertinent surface of the head of the rail to be rectified. The railroad vehicle moves along the rails of the railroad tracks to be rectified while making the best possible use of the time intervals that are available in view of the more and more intense use of rail networks.
Because of the limited length of time available to do the rectifying work, and hence the significant power of current abrading units, as well as the quality requirements for the rectifications needed, more particularly for high-speed railroad networks or networks intended for very heavy freight trains, the amounts of matter removed during a rectifying operation are very large. This is the reason why it becomes ever more important to recover the abrasive waste produced during a rectifying operation on the rails.
The abrasive waste actually consists for the most part of metal particles from the material taken off the rail surface, and for a small part of abrasive particles from the abrasive disk. The individual masses of these particles extend over a rather large range, as one has on the one hand a dust cloud consisting of particles of small mass, and on the other hand a spark jet rather well concentrated along a particular trajectory and consisting for the larger part of glowing chips having a larger mass, and notably a very high kinetic and thermal energy.
With the aim of recuperating the waste created during abrasive rail reprofiling, a device exists that comprises a box kept under reduced pressure. The box covers the top of the abrading unit and surrounds it on the sides. As described in detail in the Swiss Patent brochure CH 671,595, this device is able on the one hand to suck up from above the dust cloud consisting of particles of small mass and to transport them toward a container on the railroad vehicle in order to keep them there temporarily until they are unloaded. The lateral walls of the device on the other hand form a kind of mechanical collector possibly equipped with a deflector accumulating the heavy particles ejected with the spark jet. Because of their very high kinetic and thermal energy, these heavy particles cannot be sucked up by this device, and rapidly form accumulations of matter on the lateral walls of the box. They thus are not transported to the container in order to be effectively eliminated, but are simply dumped along the railroad track at certain time intervals.
Since the low-mass particles contained in the dust cloud sucked up by this device constitute only 10 to 20% of the abrasive waste while the remainder of the waste matter is contained in the jet of the heavy spark particles, this process does not allow a satisfactory percentage of the waste generated during abrasive rail reprofiling to be recovered. The resulting ecological disadvantage is increasingly important owing to the rising amount of waste produced during reprofiling, as explained above, as well as owing to the fact that the protection of nature in general becomes ever more important. The spark jet moreover has other negative consequences, such as an important release of heat leading to difficult working conditions for the staff in charge of the device and to a high thermal load on the components of the device. The spark jet even represents a risk of injury to the operators, and it would be desirable to eliminate this source of danger.